Bug#947955: general: Windows on second (external) screen are blurry after notebook sleep

[Matthias Brennwald <mbrennwa@gmail.com>]

Package: general
Severity: normal

I have an external screen connected to my notebook computer (Dell XPS 13).
After waking the notebook from sleep mode, the windows that have been opened
before activating sleep mode are blurry. Newly opened windows are not affected.
The issue happens with windows from all programs, not just a specific program.
Moving or resizing the windows does not change the blurry appearance. I have
reproduced the issue on a different notebook computer (HP hardware) with a
different external screen.

(Debian Testing with Gnome 3.34)



-- System Information:
Debian Release: bullseye/sid
  APT prefers testing
  APT policy: (950, 'testing'), (800, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 5.3.0-3-amd64 (SMP w/4 CPU cores)
Kernel taint flags: TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled